Speaker 1: Hey everyone, it's Stephen Ray Morris. I'm here to tell
Speaker 1: you a little bit about sleep paralysis and lucid dreaming
Speaker 1: and where the two meet in the middle, which is me.
Speaker 1: Sleeping has always been especially lately has been pretty difficult,
Speaker 1: But for most of my life I've had pretty like
Speaker 1: stressful dreams, to the point where I feel like sleep
Speaker 1: isn't very RESTful for me. When I was younger, it
Speaker 1: used to be really easy for me to fall asleep,
Speaker 1: but then the actual dreams and things themselves wouldn't be
Speaker 1: very RESTful. And that I think like a common theme
Speaker 1: in my dreams is that I have to do a
Speaker 1: task in a limited amount of time and there's an
Speaker 1: obstacle getting in the way. And some of my favorite
Speaker 1: examples of this are I am like a manager at
Speaker 1: a brothel Christmas party, and I have to make sure
Speaker 1: everybody gets their gifts, but all the gifts are unlabeled.
Speaker 1: I have to catch a train, but I keep running
Speaker 1: into people I haven't seen in a long time, so hey,
Speaker 1: nice to see I Actually I got to catch that
Speaker 1: train and then I run into somebody else. In college,
Speaker 1: I started getting sleep paralysis. I still do from time
Speaker 1: to time, but it was really bad where you know,
Speaker 1: it's your brain is awake but your body is asleep.
Speaker 1: So there's usually some sort of demon like nausicle dementor
Speaker 1: style thing in the corner of the room, and it
Speaker 1: just causes this intense fear and terror, and so I
Speaker 1: usually wake up like everyone I've ever is whatever spent
Speaker 1: the night with, have always had to deal with me
Speaker 1: waking up and screaming from these forces. In college, I
Speaker 1: met my roommate and my buddy Evan who's from the
Speaker 1: Bay Area, and you know, we all watched Waking Life,
Speaker 1: and in that movie they talk about lucy dreaming, which is,
Speaker 1: you know, the ability to be aware that you're dreaming
Speaker 1: and control your dreaming, etc.
Speaker 2: Etc.
Speaker 1: The two main things that I took away from it are,
Speaker 1: you know, like AI, look at your hands or look
Speaker 1: at clocks, because dreams can't represent either of the things
Speaker 1: very well, so if you see them, that means you
Speaker 1: know you're dreaming. So I started continuing these dreams where
Speaker 1: just this intense fear as this dark figure is looming
Speaker 1: in the corner, and I, after all this lucid dreaming
Speaker 1: training or whatever, I started to like wriggle a little
Speaker 1: bit you know, because I was so scared that I
Speaker 1: was really trying to get away. And then one night,
Speaker 1: as it got right over my bed was looming down
Speaker 1: at me, I just remember this feeling of a you know,
Speaker 1: like full like superhero movie like the strain, and I
Speaker 1: reached my hand out and grabbed this sleep process demon
Speaker 1: by the wrist, and then I woke up and I
Speaker 1: didn't have sleep process again for a few years. I
Speaker 1: still remember this so clearly like it was yesterday, even
Speaker 1: though this was maybe, like I don't know, almost twenty
Speaker 1: years ago. The sleep process still happens every once in
Speaker 1: a while, but I think my lucid dreaming training still
Speaker 1: serves me well occasionally, so I'm prepared basically anytime sleep
Speaker 1: roll Stevens come at me.
Speaker 3: Stephen, Stephen, I mean, first of all, terrifying, but also secondly,
Speaker 3: what a joy to hear your voice.
Speaker 4: Thank you so much for sharing your sleep and sleep
Speaker 4: dreams sleep paralysis story with us.
Speaker 3: It is so scary. I've had sleep proalyssis just a
Speaker 3: few times in my life and I truly thought I
Speaker 3: was dying.
Speaker 4: I know, I don't know that I've ever had it,
Speaker 4: but all of the stories that I hear, are like
Speaker 4: really terrifying.
Speaker 3: Yeah, yeah, so yeah, thank you, thank you.
Speaker 5: Hi.
Speaker 6: I'm Aaron Welsh and I'm Erin Allman.
Speaker 3: Update and this is this podcast will kill you. Welcome
Speaker 3: to the exactly Right Studio, Yes, where we will be
Speaker 3: discussing in two episodes sleep. I'm excited for this very much.
Speaker 3: So what are we going to be talking about. There's
Speaker 3: a lot that we're going to cover and we will
Speaker 3: not cover, so we are going to be typing. This
Speaker 3: first episode, we're focusing on what sleep is essentially, like,
Speaker 3: what does it entail, what is your brain doing a
Speaker 3: little bit about why sleep is important or what we
Speaker 3: think sleep is important for. I'm going to be talking
Speaker 3: about sleep in animals a lot.
Speaker 6: I'm really excited about it. I'm excited about too.
Speaker 3: I did not know where it was going to go right.
Speaker 3: And then next episode we're going to talk about some
Speaker 3: of the consequences of sleep deprivation and also we're going
Speaker 3: to be talking about the history of human sleep.
Speaker 4: I'm really excited about that too. I think the second
Speaker 4: episode is going to be a lot of interesting discussion
Speaker 4: about how we think about sleep today.
Speaker 3: I think so too. It I personally felt a lot
Speaker 3: better about sleep.
Speaker 4: Oh good, Yeah, that's great at the end of it,
Speaker 4: happy to hear it, thank you, thank you hopefully everyone,
Speaker 4: but not this week. No, this week you'll just learn
Speaker 4: a lot about sleep.
Speaker 3: Yeah, I'm excited, and you'll also have a really delicious.
Speaker 4: Beverage go along with it, right, because it's quarantin any time.
Speaker 3: It is in this case, it's plas breta time because alcohol,
Speaker 3: spoiler alert, makes you sleep badly.
Speaker 4: It's not good for your sleep, even though lots of
Speaker 4: people use it as a sleep aid, far an anxiolytic.
Speaker 6: Hmm, it's not good for either of those.
Speaker 3: I mean, alcohol is not good for anything period, not
Speaker 3: good for your body. There's no safe amount anyway.
Speaker 6: Anyways, So.
Speaker 4: Is is basically like a really nice version of a
Speaker 4: Camma meal tea.
Speaker 3: But what is it called erin it's called.
Speaker 6: Pillar talk.
Speaker 4: Yeah, the long pause of be trying to remember.
Speaker 3: Well, because we had a few different options. There was
Speaker 3: also bedtime stortory. Yeah, which would it's a great one. Yeah. Yeah,
Speaker 3: it's a Cama meal tea plus ginger, honey syrup so good,
Speaker 3: and a little bit of lemon in there.
Speaker 6: Yeah. Kind of wish we had that sound.
Speaker 3: Nice sounds good for your throat. Yeah.
Speaker 4: Anyways, but you can make one and drink along with us.
Speaker 4: We'll post the full recipe on our social media channels
Speaker 4: for sure. Maybe on our website. Aaron walk us through
Speaker 4: the website.
Speaker 3: Oh, the website. Sorry for throwing are Yeah. The website
Speaker 3: is a real joy to discover. You can find things
Speaker 3: like transcripts. You can find things like the sources for
Speaker 3: each and every one of our episodes. You can find
Speaker 3: links to our bookshop dot org affiliate page, goodreads list, merch,
Speaker 3: some pretty sweet merch. You can find links to music
Speaker 3: by Bloodmobile, to contact us, form a first hand account form,
Speaker 3: and probably some other things. There's an about us page too.
Speaker 6: Sure it's not like four lines yep, it does.
Speaker 3: Not contain a lot of information.
Speaker 6: Oh so check that out.
Speaker 4: Check it out, make sure you are rated, rate it,
Speaker 4: make sure you are rape, make sure you have subscribed
Speaker 4: and rate it.
Speaker 6: Like to review and review the podcast.
Speaker 4: We would appreciate that we're doing great. We're really killing
Speaker 4: it today. Yeah, and if you are a fan of
Speaker 4: watching things, we're on YouTube on the exactly.
Speaker 3: Right so you can see some sweet pjs that we're wearing.
Speaker 6: We're pretty excited about it.
Speaker 3: I really like, I really like yours. It's very beatle juice.
Speaker 6: Yours too, it is very beatle juice.
Speaker 3: Thank you.
Speaker 6: I love it.
Speaker 4: We took a long time picking these out, everyone, so
Speaker 4: we did. Okay, well with that.
Speaker 3: Aaron, shall we take a break.
Speaker 6: Business complete it, Business complete. Let's move on to learning
Speaker 6: about sleep.
Speaker 3: Love it?
Speaker 2: Okay.
Speaker 4: We all sleep, all of us humans, and Aarin, I
Speaker 4: know that you are going to walk us through some
Speaker 4: of the many different ways that animals sleep, which I'm
Speaker 4: quite excited about, Like what does that.
Speaker 6: Mean in animals?
Speaker 3: What does it mean?
Speaker 6: And there's such a variety there.
Speaker 3: What does it mean to humans?
Speaker 4: Well, let me tell you about it? And that's an
Speaker 4: interesting question. It's because we all sleep. I think that
Speaker 4: we all.
Speaker 6: Know what it means to sleep.
Speaker 4: One could even go so far as to say, much
Speaker 4: like the Supreme Court Justice Potter Stewart said in nineteen
Speaker 4: sixty four when trying to define hardcore pornography, I know
Speaker 4: it when I see it. Yeah, yeah, we all know
Speaker 4: what sleep is.
Speaker 6: But what is sleep?
Speaker 4: If we're trying to put like a label on it?
Speaker 4: What are our brains doing when we sleep? And these
Speaker 4: are the questions that I'm going to try and answer today,
Speaker 4: But the biggest question is one that we cannot really
Speaker 4: answer with what we know, and that is why, exactly
Speaker 4: why do we sleep? We don't really know truly the
Speaker 4: function of sleep, but we do have a lot of
Speaker 4: thoughts and hypotheses which have various levels of support. So
Speaker 4: we'll get into some of that as well, and then
Speaker 4: next week, like we said, we'll talk more about what
Speaker 4: makes good sleep good and what makes bad sleep bad?
Speaker 3: It's so, and then what about like the quantities of
Speaker 3: sleep and.
Speaker 4: Allus we'll get into the architecture of sleep. You get
Speaker 4: a dollar, okay, So what is sleep? If we define it? Sure,
Speaker 4: a simplified definition is like a reduced state of voluntary
Speaker 4: motor activity, so you're not mo you've got a decreased
Speaker 4: response to stimulation. And in general, there's a stereotypic posture
Speaker 4: associated with sleep. I know you'll talk more about that aeron,
Speaker 4: but humans, the thought postures, I know, right, in humans
Speaker 4: we lay down, right, Yeah, that's what we do for sleep.
Speaker 4: And in contrast to other states that might be similar
Speaker 4: to sleep, like say a coma, sleep is easily reversible, okay,
Speaker 4: But in reality, in medicine, we have defined sleep based
Speaker 4: on specific patterns of electrical activity in our brains e g.
Speaker 6: Egs.
Speaker 4: So let's get into it. We talked about egs or
Speaker 4: electro encephalograms in our epilepsy episode.
Speaker 3: Oh gosh, that was a long time ago.
Speaker 4: It was a while back, and at that time I
Speaker 4: was just like, I don't want to get into it, goodbye,
Speaker 4: and we just didn't.
Speaker 3: Talk to it someday today, today's the day.
Speaker 4: So EEG's measure the electrical activity happening in our brains,
Speaker 4: and the readouts of EEG's when you see them on
Speaker 4: paper or on a computer, are these wave patterns, kind
Speaker 4: of like if you've ever edited like a sound file,
Speaker 4: you see these little wave patterns. They look very similar
Speaker 4: to that. And waves, if anyone hasn't taken physics in
Speaker 4: a long time, are measured by two main main measurements,
Speaker 4: and that is amplitude.
Speaker 6: Which is the height of the waves.
Speaker 4: And frequency, which is the number of waves per second
Speaker 4: or per.
Speaker 6: Unit of time.
Speaker 4: Right, Okay, So the higher the frequency, that means the
Speaker 4: faster the waves, the closer together the waves are, and
Speaker 4: we call that a high frequency, and then lower frequency
Speaker 4: are slower waves. Okay, So longer wavelength, longer frequency. Okay,
Speaker 4: Depending on what our brain is doing, our EG makes
Speaker 4: a number of kind of predictable patterns, some of which
Speaker 4: we only see when we're awake and some of which
Speaker 4: we only really see when we're asleep. So when we're awake,
Speaker 4: our EEG pattern shows these fast frequency, low amplitude waves.
Speaker 3: Fast frequency low amplication, high frequency low altitude.
Speaker 2: Yeah.
Speaker 4: Yeah, so they're like close together waves and they're they're
Speaker 4: not they're just little little baby waves. And the most
Speaker 4: common two types of waveforms are called alpha waves and
Speaker 4: beta waves.
Speaker 6: There's a few others too.
Speaker 4: Alpha rhythms are like calm, eyes closed, like meditation type
Speaker 4: of vibes, and then beta waves are what we see
Speaker 4: more with like activity of the brain.
Speaker 3: Sorry, so we're talking about these are sleep, awake, sleep away.
Speaker 6: This is what we're doing right now. We're probably beta waving.
Speaker 3: We're definitely beta waving, not calm at all.
Speaker 4: But during sleep, our EEG patterns change and we can
Speaker 4: measure more than just the brain electricity. Actually, so when
Speaker 4: we're measuring sleep, there's three main sets of measurements that
Speaker 4: we're looking at. The EEG which is your brain electrical activity,
Speaker 4: the e MG or electro milogram, which records activity in
Speaker 4: our skeletal muscles.
Speaker 6: Okay, and then the EOG.
Speaker 4: Or electro oculogram, yes, which is measuring rapid eye movement, yes,
Speaker 4: horizontal eye movement. And if we put all three of
Speaker 4: these together, they result in what's called a polysomnogram or PSG.
Speaker 4: So you can look up a picture of a PSG.
Speaker 4: But it's like a lot of wires, a lot of Yeah,
Speaker 4: and sometimes there's more if you're measuring like your pull
Speaker 4: socks and your heart rate and things like that.
Speaker 3: Okay. I've always wondered this about sleep study things. Yeah,
Speaker 3: I feel like I would sleep terribly.
Speaker 4: I know it's a valid concern. I don't have an
Speaker 4: answer for.
Speaker 3: It, Okay, So like how okay, another question, then, how
Speaker 3: many nights will you sleep with wires, et cetera to
Speaker 3: get like a good model of what your sleep is?
Speaker 6: Like, that's a great question. I don't know a lot
Speaker 6: of a lot of times.
Speaker 4: It might just be one night, just one night, yeah,
Speaker 4: but it totally depends on what the scenario is, what
Speaker 4: the study is, and like what information they get from
Speaker 4: that kind of a thing.
Speaker 3: I find that so interesting because I feel like sleep
Speaker 3: is so variable.
Speaker 4: Oh, it's so variable, Aaron, It can totally be so variable. Yeah,
Speaker 4: So I don't have a great answer to that, Okay, yeah, yeah,
Speaker 4: totally totally depends on the study and what they're doing,
Speaker 4: what they're looking for. But based on these PSG readings,
Speaker 4: what we've done over the years in studying many people
Speaker 4: for longer periods and in the lab et cetera, we
Speaker 4: now can divide sleep into two main phases. There's REM
Speaker 4: sleep just two okay, well, two main divisions. Y, there's
Speaker 4: faces within these, but the two main divisions are REM
Speaker 4: or rapid eye movement sleep and non REM or non rapid.
Speaker 6: Eye movement sleep.
Speaker 3: Yeah.
Speaker 4: Within non REM sleep, there are three different phases sometimes four.
Speaker 4: Sometimes Stage three and four are separated.
Speaker 3: And this is just depending on classification, not like.
Speaker 4: Yeah, the older the older literature kind of says there's
Speaker 4: four stages of non REM and the newer literature is like, realistically,
Speaker 4: deep sleep is all deep sleep. We'll just call it
Speaker 4: phase three. Oh interesting, So anyways, it doesn't really matter.
Speaker 4: But let's walk through what a night of sleep looks
Speaker 4: like together. Because we fall asleep in relatively predictable patterns
Speaker 4: and as we fall asleep, our brain waves kind of
Speaker 4: get slower and slower as we go. So, like I
Speaker 4: said before, as we're awake and relaxed, our brain is
Speaker 4: in this alpha wave pattern, which is low amplitude, relatively
Speaker 4: high frequency waves. Then as we fall into stage one sleep,
Speaker 4: which is one of the stages of non rem we
Speaker 4: call it kind of drowsiness, we'll slip into this pattern
Speaker 4: called theta waves, which is slightly lower frequency, still low amplitude.
Speaker 3: Slightly lower frequency.
Speaker 4: So a little longer wavelengths and a little longer frequency
Speaker 4: than the alpha waves, but still low amplitude.
Speaker 3: Okay, little down there.
Speaker 4: Muscle eyes, you might have these little like twitches or
Speaker 4: muscle jerks as we all know why, I don't know.
Speaker 4: And then stage two is when you start to truly
Speaker 4: fall asleep. This is when conscious awareness is gone. Your
Speaker 4: muscle activity decreases substantially, and your brain waves will continue
Speaker 4: in this theta wave pattern. But then we see them
Speaker 4: punctuated by these really weird little bursts of activity, these
Speaker 4: short little bursts of super high frequency events that are
Speaker 4: called spindles, followed by what's called a K complex, which
Speaker 4: is this very it's a low frequency, high amplitude just
Speaker 4: like one two high amplitude so like wide and tall, weird?
Speaker 4: Just what and that's a k complex okay, And that's
Speaker 4: like stage two. So we see this mostly like slightly
Speaker 4: chiller pattern, then awake and then little bursts of.
Speaker 3: Ye yeah, like a heart almost like a heartbeat kind
Speaker 3: of yeah.
Speaker 4: Sure, we'll say sure, yeah. And then after stage two
Speaker 4: we fall into deep sleep or slow wave sleep.
Speaker 3: Stage three, I'm guessing frequency goes down, yeah, tell me
Speaker 3: about amplitude.
Speaker 4: Amplitude goes up. So we see this high amplitude low
Speaker 4: low frequency slow waves that we call delta waves.
Speaker 3: What is what does it mean to have high amplitude?
Speaker 5: You know?
Speaker 3: Yeah?
Speaker 4: So the waves are created essentially by this like activity
Speaker 4: of our neurotransmitters happening all at once, and so really
Speaker 4: it's that the activity patterns in various parts of our
Speaker 4: brain have slowed down, essentially, is what we're seeing.
Speaker 3: For the frequency, right, And what about the amplitude.
Speaker 4: I don't know the answer, amplitude, Yeah, I really don't.
Speaker 4: This is why I'm like not an EEG expert, and
Speaker 4: maybe someone who is can let us know.
Speaker 6: I don't.
Speaker 4: But that is deep sleep or slow wave sleep so
Speaker 4: we'll stay in that sleep for a period of time,
Speaker 4: don't know how long, depends on you, and then we
Speaker 4: pop up quickly to stage two. We pass through that
Speaker 4: pretty quickly, and then we enter our first rem sleep
Speaker 4: of the night.
Speaker 3: So deep sleep is one. That's stage that's the first
Speaker 3: thing that we encounter.
Speaker 4: No, we go we go stage one, Stage two, Stage three,
Speaker 4: which is deep sleep.
Speaker 6: Oh, okay, we'll stay.
Speaker 4: There for a little while, and then we'll go stage two.
Speaker 4: Rem got it, okay. And in contrast to all these
Speaker 4: other sleep patterns where waves are getting longer and in
Speaker 4: REM sleep, your brain EEG pattern looks like you're awake.
Speaker 4: It is an awake beta wave, so not even like
Speaker 4: a calm alpha wave pattern. It's like a beta wave.
Speaker 4: This is a type of pattern.
Speaker 3: Like we're recording an episode in our sleep. Our sleep.
Speaker 4: And REM sleep is also characterized by like a more
Speaker 4: awake type of physio. Our blood pressure is higher, our
Speaker 4: heart rate is higher, our respiratory rate is higher compared
Speaker 4: to non REM sleep.
Speaker 3: What about our temperature our body temp.
Speaker 4: Oh, that's a good question. I think our body temperature
Speaker 4: goes up as well too. Okay, still probably not quite
Speaker 4: as high as it is because in general our body
Speaker 4: temperature falls with sleep, but it's going to go up
Speaker 4: compared to deep sleep. Okay, however, we have two weird
Speaker 4: things happening in REM sleep that we do not see
Speaker 4: when we're awake, and that is these rapid horizontal eye
Speaker 4: movements Yep, that happen, and our skeletal muscle activity is
Speaker 4: essentially atonic.
Speaker 6: We really do not move.
Speaker 3: We don't so we move even less than we do
Speaker 3: in our falling asleep twitchy.
Speaker 4: Correct, Yeah, you might still have occasional muscle twitches, but
Speaker 4: in general, your skeletal muscles, so like arms and legs,
Speaker 4: are not really moving.
Speaker 3: I know that this is all foundational, so that someday
Speaker 3: we will talk about sleep disorders in more details. Yeah,
Speaker 3: but it is making me want to ask one thousand
Speaker 3: and one question. Yeah about like what happens when sleepwalking anyway?
Speaker 4: We yeah, yeah, sleepwalking is something you'd see more in
Speaker 4: the deep sleep. In the deep sleep, right, because you're
Speaker 4: again in REM sleep, your muscles are not moving, right,
Speaker 4: so in REM sleep we can see things like sleep paralysis.
Speaker 4: We think that that's like.
Speaker 3: You're yeah, because you can't move, you're.
Speaker 4: Having basically rem sleep muscle activity, but with an awake
Speaker 4: brain where you actually do wake up. And that's what
Speaker 4: we think is happening in sleep paralysis.
Speaker 6: And that's all I'm going to talk about when it
Speaker 6: comes to dreams.
Speaker 3: Yeah, FYI.
Speaker 4: So in a night of sleep, we cycle through both
Speaker 4: non REM and REM sleep in a pretty typical pattern.
Speaker 4: We go from stage one to two to three that
Speaker 4: quick pickstop at two and then back up to REM
Speaker 4: and that once we end that REM cycle is considered
Speaker 4: one sleep cycle. And in adults, a sleep cycle lasts
Speaker 4: between like ninety and one hundred or so minutes. Okay,
Speaker 4: so depending on how long you sleep at night, we
Speaker 4: might go through like four or five or more of
Speaker 4: these cycles.
Speaker 3: Okay, I have a question about give it to me
Speaker 3: the REM like deep sleep. So I remember reading that
Speaker 3: deep sleep happens early on in the night. Correct, yes, why,
Speaker 3: and but REM sleep happens throughout.
Speaker 4: We tend to have more deep sleep early in the night,
Speaker 4: and then like shorter periods of REM sleep earlier in
Speaker 4: the night and longer periods of REM sleep later in
Speaker 4: the night, and then it's possible that you might not
Speaker 4: like later in the night, drop all the way down
Speaker 4: to that deep sleep like stage three n REM, you
Speaker 4: might maybe just go to stage two then up to
Speaker 4: REM a couple of times in your later sleep cycles.
Speaker 6: Yes, that is true.
Speaker 4: Why I don't know Erin It's also really interesting because
Speaker 4: like the amount of deep sleep that you get also
Speaker 4: correlates to how much sleep you got, say, the night before.
Speaker 4: So if you are sleep deprived and you're running off
Speaker 4: of like sleep debt as they sometimes call it, then
Speaker 4: your next night of sleep will likely have more of
Speaker 4: that slow wave or deep sleep compared to the night
Speaker 4: before recovery sleep.
Speaker 3: Kind of, So the in terms of the breakdown of
Speaker 3: like I'm the sleep cycle, not even like the number,
Speaker 3: but just the proportion overall. I'm getting ahead of things
Speaker 3: you are. Yeah, but I'm what proportion of sleep quote
Speaker 3: unquote should be REM, should be deep sleep, should be whatever?
Speaker 3: Stage two?
Speaker 4: Yeah, it depends on your age and your stage of
Speaker 4: life and things like that. So babies have like a
Speaker 4: lot more REM sleep than adults. They've got like over
Speaker 4: forty percent REM sleep. Adults it's usually twenty to thirty
Speaker 4: percent is considered typical, and then twenty I think it's
Speaker 4: like fifteen to twenty percent. It's in my notes from
Speaker 4: next episodes, so we'll get more into it. But yeah,
Speaker 4: it's usually like fifteen to twenty percent or so. Is
Speaker 4: deep sleep oh or should be deep sleep typical deep?
Speaker 3: Oh my gosh, I mean.
Speaker 4: And then the rest is that like stage two type
Speaker 4: of sleep stage yeah, or bouncing between you know, stage
Speaker 4: one and stage two.
Speaker 3: Sort of like that, which is not I mean I
Speaker 3: feel like deep sleep and RAM are like the stars
Speaker 3: of the show.
Speaker 4: Yeah, they get the crag even though you're not the
Speaker 4: majority of your.
Speaker 3: Sleep, right, which is also important.
Speaker 4: It is it is, Yeah, but that is like how
Speaker 4: your sleep cycle goes throughout the night, and it is
Speaker 4: going to depend how much time you spend in each
Speaker 4: one of these from night to night, from person to person,
Speaker 4: And anybody who has one of those rings or one
Speaker 4: of those watches that's monitoring your sleep knows that these
Speaker 4: things are going to.
Speaker 6: Very night tonight.
Speaker 4: Yeah, So, speaking of which, I just wanted to good.
Speaker 3: Yeah, I'm glad you're talking about I just wanted.
Speaker 4: To talk about these real quick because there is so
Speaker 4: much out there right now that's like you need one
Speaker 4: of these rings to monitor your sleep, and you need
Speaker 4: to be monitoring your sleep, and these are this one
Speaker 4: is the best one to be monitoring it, et cetera.
Speaker 4: I found a paper that was not sponsored by the
Speaker 4: manufacturer of any of these devices, just the one.
Speaker 3: Just one.
Speaker 6: There's a lot of.
Speaker 4: Papers that are sponsored by that were like funded by
Speaker 4: the manufacturing of these things, who will say like, oh,
Speaker 4: these are like seventy five to eighty percent accurate compared
Speaker 4: to PSGs, Like these are super super accurate. So I
Speaker 4: found one paper that was comparing a number of different rings.
Speaker 4: It wasn't as much looking at the watches that was
Speaker 4: trying to figure out could these be as good as
Speaker 4: PSGs that we do in clinic, which is really important
Speaker 4: because especially to diagnose a lot of sleep disorders, like.
Speaker 3: You do need this data, and it's like accessibility and
Speaker 3: these and all of these things.
Speaker 4: Right, So it's like if we could use these clinically,
Speaker 4: that would be really awesome.
Speaker 3: Right, And then you're not having to wear all of
Speaker 3: these tubes that make you sleep poorly and then you're
Speaker 3: like you're a terrible sleeper. You need all these things.
Speaker 3: And it's like I was just.
Speaker 4: Had well and like the ability to be able to
Speaker 4: do it at home is so yeah. So there's so
Speaker 4: much that would be great if these things were really great,
Speaker 4: The problem is that they're not.
Speaker 6: And it's not that they're not decent.
Speaker 4: But I will quote here because I think that this
Speaker 4: quote kind of summarizes it all. What they said was
Speaker 4: that even the ones that correlate very strongly with the PSGs,
Speaker 4: who like on average, agree with what the PSG readings are,
Speaker 4: they said that quote this agreement masks substantial individual level inaccuracies,
Speaker 4: prohibiting their use in clinical sleep medicine, as accurate assessment
Speaker 4: of individual nights, including both nights with exceptionally low or
Speaker 4: high quality and quantity, is essential for patient care. So
Speaker 4: like on average, if you're just looking like population wide,
Speaker 4: sure they decently, they do decently well, but on a
Speaker 4: night to night basis, there's a lot of variability in
Speaker 4: how well it's capturing you as an individual.
Speaker 3: That makes sense. So you can't wake up in the
Speaker 3: morning and go, how was last night?
Speaker 6: Right?
Speaker 3: Oh yeah, I see what happened? Yes, yeah, yeah, yeah,
Speaker 3: like we did this morning.
Speaker 4: We did like we've been doing the last couple of weeks.
Speaker 4: So yeah, So that's just what I want to say
Speaker 4: about those It's like they're not I.
Speaker 3: Have heard that, Like, so they're not great at distinguishing
Speaker 3: between among the stages of sleep, correct, But they are
Speaker 3: okay at distinguishing awake and sleep.
Speaker 4: Yes, so like to get like total duration, they're pretty decent.
Speaker 4: But again, if you're trying to like understand especially like
Speaker 4: quality what we call quality and like differentiating between the
Speaker 4: different stages and things like that, or even if you're
Speaker 4: trying to and this paper was specifically more looking at
Speaker 4: people who have, say like obstructive sleep apnea or some
Speaker 4: other kind of sleep disorder where you really want to
Speaker 4: be able to get that fine detail, they weren't going
Speaker 4: to be effective for that. And most of the studies
Speaker 4: funded by the manufacturers are looking at like the general population,
Speaker 4: so like healthy people without any diagnosed sleep disorders or anything.
Speaker 4: So it's also a different population level.
Speaker 6: That we're looking at, right.
Speaker 4: So yeah, so that's what we know about those devices.
Speaker 4: Moving on, before I get too deep into like why
Speaker 4: what is happening? We know now what our brains are
Speaker 4: doing as we monitor them, But before we get into
Speaker 4: the maybe why of it, I want to touch base
Speaker 4: really quickly on kind of how we sleep, Like what
Speaker 4: is driving our sleep?
Speaker 6: Okay, okay, sleep drive, sleep drive. That's the answer.
Speaker 4: We did talk a little bit about this in our
Speaker 4: circadian rhythm episode, yes, because our circadian rhythm is one
Speaker 4: of the drivers of our sleep. So as a recap
Speaker 4: so that you don't have to listen to that episode again.
Speaker 4: There's a collection of cells deep in like the center
Speaker 4: front of our brain behind our eyes, deep in our
Speaker 4: brain that's called the super chismatic nucleus that is the
Speaker 4: clock of our brain, then the SCN and it basically
Speaker 4: generates this close to twenty four hour rhythm. All of
Speaker 4: our cells do this to one degree or another.
Speaker 3: Which is really cool.
Speaker 6: It's so cool.
Speaker 4: But this is like the master clock that keeps all
Speaker 4: of our body functions in sync, mostly using signals from
Speaker 4: light and dark from the sun. Right, and this circadian
Speaker 4: clock of ours drives things like hormone production, among many
Speaker 4: other things that help to promote sleep and awake at
Speaker 4: the right times of day and night for us as
Speaker 4: diurnal creatures. But our brain also has other mechanisms aside
Speaker 4: from just the circadian clock that help to promote both
Speaker 4: sleep and wakefulness or what's called arousal in the literature,
Speaker 4: and it's mostly parts of our brain stem.
Speaker 3: Right.
Speaker 4: And our brain stem is like the deep back part
Speaker 4: of our brain that connects to our spinal cord.
Speaker 3: The stem.
Speaker 4: The stem and parts of our brainstem release a whole
Speaker 4: bunch of neurotransmitters that are involved mostly in promoting wakefulness
Speaker 4: in wakefulness, right, so promoting us being awake and active
Speaker 4: during the day. These are things like histamine, dopamine, nor adrenaline, serotonin,
Speaker 4: all of these types of things that act in other
Speaker 4: parts of our brain to be like, go do things
Speaker 4: be awake? Yeah, that's what I imagine they're saying. And we
Speaker 4: think that sleep ends up happening from a couple things
Speaker 4: changing in our brain. One is that there's other parts
Speaker 4: of our brain closer towards the front of it that
Speaker 4: send signals to start to inhibit those awake signals. So like,
Speaker 4: at some point in the day, other parts of our
Speaker 4: brain will send signals and be like, hey, listen, histamine,
Speaker 4: chill out a little bit. You've done enough today, So
Speaker 4: they'll start to inhibit the release of histamine, ou rexin
Speaker 4: or other signals that are saying be awake.
Speaker 3: Be awake, right, and so okay.
Speaker 4: And then the other part alway, Yeah, the other part
Speaker 4: is that and this I think is really interesting we
Speaker 4: also during the day, like just with our normal metabolism,
Speaker 4: how our brain is functioning all day long, we are
Speaker 4: making a bunch of stuff, and some of those things
Speaker 4: we think act as like sleepy substances, where as they
Speaker 4: build up in our brains throughout the day. As the
Speaker 4: concentration of this substance or these substances really accumulate a
Speaker 4: our body tissues, including our brain, they increase sleep pressure.
Speaker 3: Yeah.
Speaker 6: One of the.
Speaker 4: Classic ones of these is a dentosine m HM and
Speaker 4: a denizine we produce just as a byproduct of metabolism,
Speaker 4: but as we produce that and it builds up in
Speaker 4: our brain, it makes us more sleepy. Caffeine, Yes, we
Speaker 4: talked about I was just about to ask about caffeine.
Speaker 4: Caffeine inhibits the A dentizine receptors, so it tricks our
Speaker 4: brain into thinking that we don't have a build up
Speaker 4: of this sleepy substance when we actually do, and that's
Speaker 4: how it works.
Speaker 6: To keep us awake.
Speaker 3: What about like mourning though, because if we're starting, are
Speaker 3: we starting the day fresh? Everything's cleared out? Tell me
Speaker 3: again about caffeine. It's been way too long since that episode.
Speaker 6: So caffeine.
Speaker 4: Basically like we because we're making a dentizine, just like
Speaker 4: from metabolism, we break down atp we make a dentizine.
Speaker 4: So throughout the day, it's just going to build up,
Speaker 4: build up, build up, build up, and it's going to
Speaker 4: bind to these receptors that do inhibition stuff.
Speaker 6: That's like go to sleep, go to sleep.
Speaker 4: Caffeine binds to those receptors, right, So it doesn't matter
Speaker 4: how much a dentizy you have, there's nothing for them
Speaker 4: to bind too, got it, because caffeine is blocking them,
Speaker 4: and so it tricks our brain into being like there's
Speaker 4: no identity here, I don't need to go to sleep,
Speaker 4: and it is quite effective. Like there's so many studies
Speaker 4: on like caffeine helping to alleviate sleepiness.
Speaker 3: I think that like what is so interesting? Okay, speaking
Speaker 3: for myself, Yeah, I feel like when if I am
Speaker 3: sleepy during the day or in the evening or whatever,
Speaker 3: just at any point in the day, I'm like, I
Speaker 3: didn't get good sleep. I'm really tired, and I feel
Speaker 3: like I expect that if to get really good sleep
Speaker 3: or getting really good sleep makes me have no sleep drive,
Speaker 3: and that's the ideal.
Speaker 6: Oh, that's so interesting, you know what I mean? Yea,
Speaker 6: I shouldn't ever be sleeping.
Speaker 3: I shouldn't be sleepy until it's right before bed. And
Speaker 3: now I just laid back, close my eyes and I'm
Speaker 3: out boom, and I'm like, that would be great.
Speaker 4: I would be great, But like it's not realistic.
Speaker 3: It's not realistic. So sleep drive is so important, is
Speaker 3: what I'm saying.
Speaker 4: Well, and it's also it's interesting too because there is
Speaker 4: this there's like a build up of our sleep drive
Speaker 4: versus our circadian rhythm, and so sometimes those kind of
Speaker 4: cross paths at a weird time where we can get
Speaker 4: more sleepy than we expect in like the middle afternoon
Speaker 4: or something like that. And so that's part of why
Speaker 4: we might feel sleepy at times of day where we think, like,
Speaker 4: I don't understand why I feel sleepy right now, and
Speaker 4: it's just maybe because things are you know, it hasn't
Speaker 4: overlapped in exactly the right way today kind of a thing,
Speaker 4: But it doesn't necessarily mean that your sleep was terrible
Speaker 4: the night before, right, So it is really interesting and
Speaker 4: I'm probably not doing it justice, but there's obviously a
Speaker 4: lot and it's not just a dentizy.
Speaker 6: Right.
Speaker 4: There's a lot of other substances that we think are
Speaker 4: involved in this. So there's a lot that goes into
Speaker 4: when and how we're sleepy. And some of it, too,
Speaker 4: is genetics. So we know that some of our sleep
Speaker 4: drive and a lot of our circadian rhythm, like whether
Speaker 4: we are a night owl or a morning bird morning
Speaker 4: morning lark, like, some of that is genetics. There's also
Speaker 4: some genetic markers that we think are associated with like
Speaker 4: very short sleep where people sleep very little but are
Speaker 4: totally fine.
Speaker 6: Oh yeah, right, And.
Speaker 4: Our need for and our pattern of sleep also changes drastically.
Speaker 6: Over our lifetime.
Speaker 3: It does.
Speaker 4: My favorite example of this are tiny babies.
Speaker 6: Oh yeah, because.
Speaker 4: Even though fetus is sleep when they are still in utero,
Speaker 4: they do that like mostly in sync with the human
Speaker 4: who's housing them. But once a baby is born, they
Speaker 4: do not have a well defined circadian clock.
Speaker 3: It's a mess, it is a disaster, yea.
Speaker 4: Their circadian clock is much less than twenty four hours,
Speaker 4: and their sleep pattern, like I said, a sleep cycle
Speaker 4: is like ninety minutes. It's much shorter in babies, so
Speaker 4: they're also cycling through a whole cycle of sleep in
Speaker 4: much less time, yep, and their sleep pattern is totally random, yeah,
Speaker 4: completely random, and they'll sleep up till like hours a
Speaker 4: day like a dog, and not in any pattern that's
Speaker 4: compatible with adult sleep patterns. And it's not until the
Speaker 4: first like six to twelve months of life that they
Speaker 4: start to consolidate their sleep into these twenty four hour patterns.
Speaker 4: And because I fell into what is very common these
Speaker 4: days of being very obsessive about my infant sleep when
Speaker 4: my first child was born, I have data that you
Speaker 4: can check out if you're watching the YouTube of my
Speaker 4: kid's sleep pattern when he was an infant, and you
Speaker 4: can see that it is literally all over the place.
Speaker 3: I don't think anyone listening is surprised that you collected
Speaker 3: data for how many months.
Speaker 6: Of your first kids life? So many months?
Speaker 3: Many? I mean the first probably fifteen. That's just one
Speaker 3: aspect I had. The amount of date I remember too.
Speaker 4: There was so much. Yeah, the second one I didn't
Speaker 4: do any of that. But you can then see that
Speaker 4: by eleven or twelve months, even though sleep wasn't great,
Speaker 4: you can see this twenty four hour pattern emerge where
Speaker 4: there's like a nap in the middle of the day
Speaker 4: or maybe two naps, But then the majority of sleep
Speaker 4: is happening over the night time period, and that is
Speaker 4: because that's how long it really takes for infants to
Speaker 4: develop this twenty four hour pattern, which I think is
Speaker 4: just so interesting. And then the amount of sleep that
Speaker 4: we need over our lifetime changes too. Kids need a
Speaker 4: lot more sleep. Teenagers we talked about in our circadian
Speaker 4: rhythm episode do actually have a shift in their circadian
Speaker 4: rhythm towards night owl tendencies, and so they tend to
Speaker 4: sleep later and wake up later, and that can put
Speaker 4: them out of sync with our modern society. And then
Speaker 4: as adults, especially older adults, a lot of times we
Speaker 4: don't need quite as much sleep. So the amount of
Speaker 4: sleep that we actually need varies. So why do we
Speaker 4: need this much sleep? Like why I'm I'm but it's
Speaker 4: a rhetorical question that I'm going to try and answer,
Speaker 4: asking the room ask does anybody know?
Speaker 3: Does anyone know?
Speaker 6: We still like, we still don't really know.
Speaker 3: We don't exactly.
Speaker 4: What our brains are doing in terms of the function
Speaker 4: of our sleep, Like.
Speaker 3: We know what happens. We know there are bad things
Speaker 3: that happen when we don't get enough skit correct and
Speaker 3: that's a lot about that. That's what guides a lot
Speaker 3: of our assumptions about why sleep is important.
Speaker 4: Yes, and like what our brains are really like doing
Speaker 4: during sleep. Yeah, so we do see and the one
Speaker 4: of the hypotheses I'll kind of walk through the biggest ones.
Speaker 4: One of the hypotheses is that it is kind of
Speaker 4: energy conservation during sleep, and that is because we do
Speaker 4: see a relative decrease in metabolism during sleep.
Speaker 3: However, not really, I mean especially yeah, yeah.
Speaker 4: Yeah, especially if you're looking at total body metabolism, Like
Speaker 4: during rem sleep, our metabolism is essentially the same as
Speaker 4: when we're awake. Our brain metabolism does decrease substantially, especially
Speaker 4: during non rem sleep, but again that's only a portion
Speaker 4: of our total sleep, right, and it's nothing like like
Speaker 4: our sleep is nothing like hibernation or torpor or something
Speaker 4: where we're truly decreasing metabolism.
Speaker 6: So that's clearly not the whole story. Could be part
Speaker 6: of it.
Speaker 4: There is a lot of evidence that we see changes
Speaker 4: in things like gene expression, so like certain things turn
Speaker 4: on and certain things turn off when we're asleep. That
Speaker 4: only happens when we're asleep, So we think that must
Speaker 4: be important. But why exactly We don't know. I mean, yeah,
Speaker 4: because I talked about these like sleepy substances and things
Speaker 4: like that. We do think that there's sort of like
Speaker 4: a clean out of the build up of these neurotransmitters
Speaker 4: that happens during the day.
Speaker 3: Detox.
Speaker 6: Yeah, brain detox. I hate that word.
Speaker 4: It's not accurate, but but we do see like an
Speaker 4: increase of cerebral spinal fluid flow during sleep and things.
Speaker 3: Wash was so I've just heard it described getting rid
Speaker 3: of all these neurotransmitters and replenishing others. It's very like
Speaker 3: it's a very satisfying image to think about, just like
Speaker 3: just like a gentle washing of the brain.
Speaker 4: That's what you're hearing as you all asleep anyways, great
Speaker 4: white noise. How much of is that the function of sleep?
Speaker 6: Maybe?
Speaker 3: Yeah.
Speaker 4: And then one of the biggest hypotheses is that sleep
Speaker 4: is required for consolidation of our memory.
Speaker 3: Memory consolidation. Why do we have to whisper?
Speaker 4: I don't know, And we do know there's something called
Speaker 4: sleep dependent memory processing where there's done. We've done a
Speaker 4: bunch of studies where if you give humans or animals
Speaker 4: a task and then deprive them of sleep. They never
Speaker 4: really learn that task to the same degree that they
Speaker 4: would if you let them sleep after it. But even this,
Speaker 4: the data is a little it's a little bit controversial
Speaker 4: still that like is this truly the function of sleep,
Speaker 4: especially because it's like we're trying to compare human brains
Speaker 4: to like, well, we don't have like lots of animals
Speaker 4: sleep that don't we don't know anything about their memory.
Speaker 6: Oh you'll get to it. You'll get it with those eyebrows.
Speaker 3: Sorry, I love it, but but.
Speaker 4: Yeah, that's that is one of the kind of big
Speaker 4: hypotheses that like sleep is essential for our memory.
Speaker 3: Okay, but like I don't understand why that's controversial, only
Speaker 3: in that if it's overstated that this is the function.
Speaker 6: That's what it is. That's what it is. It's that
Speaker 6: it like we know that it's essential.
Speaker 3: It is a function.
Speaker 6: It is a function. But I think I think.
Speaker 4: That it's just that people are so obsessed with this
Speaker 4: idea that there is like a reason for things.
Speaker 3: Nah, that's just sorry, but that's true, right, Like it's
Speaker 3: not we're not going to get to oh like this
Speaker 3: like like Laurie will not will not arrive.
Speaker 6: It's a bunch of different things happen when we sleep.
Speaker 3: I know I'm not satisfying as right, we found it.
Speaker 3: Here is the answer, the reason for sleep. Right the
Speaker 3: singular point, that's ridiculous.
Speaker 4: We sleep for a bunch of different reasons, and as
Speaker 4: we'll see you next episode.
Speaker 6: If we don't, there's.
Speaker 3: A problem a lot of different things beyond memory.
Speaker 6: But that's for next episode.
Speaker 4: So, Aaron, what I'd like to know from you please
Speaker 4: is like, obviously, I know my dog sleeps.
Speaker 6: My cat all he does is sleep?
Speaker 3: Yeah?
Speaker 6: Do all animals sleep?
Speaker 5: Like?
Speaker 3: Oh?
Speaker 6: Do they?
Speaker 7: I'll tell you, Okay.
Speaker 3: In nineteen seventy one, renowned sleep researcher Alan Rechschaffen wrote
Speaker 3: that quote, if sleep does not serve an absolute vital function,
Speaker 3: then it is the biggest mistake the evolutionary process has
Speaker 3: ever made.
Speaker 6: I love that, right. Yeah, okay, So.
Speaker 3: Let's break that statement down first. Why would sleep be
Speaker 3: a mistake? Gives us vulnerable to predators and bugs and
Speaker 3: parasites transmitted by bugs, and it takes up precious time
Speaker 3: that we could be using to do something else like
Speaker 3: forage or mate or socialize or read a book, or
Speaker 3: do your taxes or play with your kids, or exercise,
Speaker 3: or cook a nice meal, or work more hours at
Speaker 3: the office. It's so true, so many things. I know
Speaker 3: that many tech bros view sleep as a mistake.
Speaker 6: Oh yeah, you don't even need it.
Speaker 3: You don't need it, You could just wake up it
Speaker 3: three am. Sorry, Wow, I think something just happened there.
Speaker 3: I liked it, but I mean that aside, though, I
Speaker 3: do think that most of us have, at one point
Speaker 3: in our lives wish that we didn't have to sleep
Speaker 3: as much as we did because we could get so
Speaker 3: much more done. I know that I have wished that,
Speaker 3: Like gosh, I could just if I didn't have to
Speaker 3: sleep as much, I could do things I wanted to do.
Speaker 3: It is undeniable that sleep is costly, but it would
Speaker 3: only be a mistake if we didn't get anything out
Speaker 3: of it. Okay, Second, does sleep serve a vital function?
Speaker 3: From what you just told us, erin, it serves multiple
Speaker 3: vital functions. We may not know precisely how sleep helps
Speaker 3: us and the pathways that it works along, but we
Speaker 3: know from experimental and observational research that sleep deprivation is harmful,
Speaker 3: and that when we lose out on sleep, our body
Speaker 3: compensates by increasing sleep. There's like sleep homeostasis kind of
Speaker 3: totally okay, So now why would sleep be the biggest
Speaker 3: mistake that the evolutionary process ever made? Because sleep is
Speaker 3: ubiquitous across the animal kingdom?
Speaker 6: Love this.
Speaker 3: At this point in our understanding of sleep, it would
Speaker 3: be much harder to prove that an animal doesn't sleep
Speaker 3: than determine that it does. Even cavefish species like the
Speaker 3: Mexican blind cavefish, which has lost eyes and pigmentation and
Speaker 3: much of their circadian rhythm pattern.
Speaker 6: Because they're in the completely.
Speaker 3: Darkness, they still retain some sleep. Wow, it's reduced as
Speaker 3: much as like eighty percent, but still there are indications
Speaker 3: of sleep. What does indications of sleep means?
Speaker 6: Especially in a fit?
Speaker 3: I know?
Speaker 6: Okay?
Speaker 3: So for us to recognize and measure sleep in non
Speaker 3: human animals, we have to step outside of our human box. So,
Speaker 3: for one, there's the logistical challenge of recording an EEG
Speaker 3: on a Mexican blind.
Speaker 6: Kfish, Like that's can you do it?
Speaker 3: Can you do it? I don't know, it's pretty difficult, challenging.
Speaker 3: And then for two, we want to be able to
Speaker 3: observe sleep in more natural settings. And for three it's
Speaker 3: important to step back from our tendency to make humans
Speaker 3: like the ideal of the norm, right, like, oh, if
Speaker 3: you don't sleep like a human, are you sleeping at all?
Speaker 3: So we can measure sleep elect electrophysiologically using EEGs, and
Speaker 3: we have done that for a number of animal species,
Speaker 3: and we can measure it behaviorally. So researchers use five
Speaker 3: criteria to say that an animal sleeps. Number one, and
Speaker 3: it's very similar like you mentioned some of these. Number
Speaker 3: one prolonged behavioral quiescence basically stop doing stuff, not doing stuff,
Speaker 3: not doing it. Number two reversible upon stimulation, unlike like
Speaker 3: you said, torpor or coma. Three a species specific posture,
Speaker 3: it's not just him, and like laying down or tucking
Speaker 3: your antenna away. And then I have a picture of
Speaker 3: my dog in bagel formation, which is a very he's
Speaker 3: one of his favorites. Number four increased arousal threshold. So
Speaker 3: you need a louder or like more substantial stimulus like
Speaker 3: a noise to get you to respond that if you're awake.
Speaker 4: Decreased response to stimulations you maybe like whispering like hey
Speaker 4: wake up now.
Speaker 6: Would you please roll over? Might not do it?
Speaker 3: You're snoring, So like your senses are dulled and number
Speaker 3: five rebound after being sleep deprived, you sleep more. And
Speaker 3: so these are the things that we can use to
Speaker 3: say that animal is sleeping because it's doing all these things.
Speaker 3: And so using these criteria, we can describe and define
Speaker 3: sleep in a huge array of species like pond snails, octopus, cuttlefish,
Speaker 3: which may even exhibit rem sleep.
Speaker 5: Sorry snails, snails, Oh, it gets even more extreme, yeah, lobsters, mice, armadillos, flies,
Speaker 5: And funnily enough, whether animals truly sleep is kind of
Speaker 5: a more recent question.
Speaker 3: Ancient scholars like Aristotle fully believed that animals sleep. Of
Speaker 3: course they sleep. And there's an adorable quote I'm going
Speaker 3: to read to you from an eighteen sixty five book
Speaker 3: called Yearbook of Facts. Quote. An insect composes itself to
Speaker 3: sleep with its antenna folded. Some of the beetles adjust
Speaker 3: them to their breast. The butterfly seeks some particular aspect
Speaker 3: of a tree and folds vertically its wings, throws back
Speaker 3: the antennae, and remains motionless and insensible to all external circumstances.
Speaker 3: When caterpillars, which are insatiable feeders, are observed resting, immovable
Speaker 3: with their heads down. They are asleep.
Speaker 6: I love it.
Speaker 4: Quote like we don't eat an eeg bro look at
Speaker 4: the book.
Speaker 3: At their little antennae, they're all yeah.
Speaker 6: And you can hear them quietly towering. Yeah. So it's
Speaker 6: so cute.
Speaker 3: But it's still helpful to have these specific standards for
Speaker 3: what counts as sleep because we can then also try
Speaker 3: to trace the genetic basis and neurological pathways of sleep. Okay, So,
Speaker 3: for example, Sea Elegance, the research world's favorite worm, contains
Speaker 3: a mere three hundred and two neurons, wow, compared to
Speaker 3: an adult fruitfly, which has two hundred and fifty thousand.
Speaker 3: So right, and since Sea Elegant sleeps, we can map
Speaker 3: out the neural pathway of sleep at least in that
Speaker 3: critter because there are so few.
Speaker 6: Wow.
Speaker 3: That's really cool, Okay, really cool. But what's even more
Speaker 3: amazing is that this isn't the quote unquote like simplest
Speaker 3: creature to sleep. Using those behavioral criteria, researchers concluded that
Speaker 3: the upside down jellyfish in the genus Cassiopeia sleep.
Speaker 6: Jellyfish jellyfish jellyfish.
Speaker 3: Unlike sea elegans, these jellyfish. They don't have a central
Speaker 3: nervous just a nerve net like rings of neurons, And
Speaker 3: so scientists observed that when the jellyfish is active, their
Speaker 3: nerve net contracts and causes pulsing behavior that lets them
Speaker 3: feed and get nutrients. But at night, the pulsing behavior
Speaker 3: reduces and they become less responsive to external stimuli. And
Speaker 3: then when you disrupt their resting time, like you keep
Speaker 3: splashing them with water waves or whatever, they will pulse
Speaker 3: even less the next day, indicative of sleep rebound. Oh
Speaker 3: my gosh, right, I love it, isn't that wild? Yes,
Speaker 3: And so this means that sleep likely evolved before a
Speaker 3: central nervous system.
Speaker 4: That is so interesting, huge, huge, especially the context of
Speaker 4: memory and stuff like that.
Speaker 8: Right, I mean, okay, yeah, okay, yeah, yeah yeah. But
Speaker 8: like this is this is an ancient and widespread thing,
Speaker 8: and so given how ancient and widespread it is, it
Speaker 8: doesn't really seem like uh.
Speaker 3: Sleep is it is a mistake. And as far as
Speaker 3: I mean, sleep doesn't get fossilized because it's a behavior.
Speaker 3: But as far as we can tell, no species has
Speaker 3: entirely lost the capacity for sleep, meaning that it is
Speaker 3: still so vital too existence. Yeah. Yeah, sleep disturbances or
Speaker 3: a lack of sleep can have profound effects on health
Speaker 3: and overall performance, vulnerability to infections, attentiveness, reaction time, memory formation.
Speaker 3: Mollusks that have been deprived of sleep cannot form new memories.
Speaker 4: So like, how do you measure a mollusc's memory?
Speaker 3: I don't know. I didn't go that deep.
Speaker 6: Now I need to.
Speaker 3: I will find the paper, right, And then there are
Speaker 3: a few gruesome experiments where rats that were completely deprived
Speaker 3: of sleep for like a long period of time died.
Speaker 6: Oh my god, they died.
Speaker 3: Yeah. The world record for no sleep, sleep deprivation and
Speaker 3: a human is eleven days. I heard that two hundred
Speaker 3: and sixty four hours, held by a San Diego teenager
Speaker 3: named Randy Gardner who in nineteen sixty five played basketball
Speaker 3: throughout the night to stay awake. But apparently, like I
Speaker 3: think in I don't know how they determine this, but
Speaker 3: they were discovering that he was taking like microground, as
Speaker 3: of course he was, and so was it truly two
Speaker 3: hundred and sixty four hours?
Speaker 1: You know?
Speaker 6: Yeah, I mean his brain was falling asleep. He just
Speaker 6: did not know it.
Speaker 3: He didn't know it, and no one else knew that
Speaker 3: he was. Yeah, but any that's like, I do not
Speaker 3: try that at home situation. Yeah, So even though we
Speaker 3: all sleep in some capacity, we don't all sleep the same.
Speaker 3: Elephants sleep about half the time that humans do, four
Speaker 3: hours compared to our eight, which is really more like
Speaker 3: six to seven. Brown bats sleep about nineteen hours a day,
Speaker 3: similar to Armadilla's. Koala's sleep even longer, twenty to twenty
Speaker 3: two hours. Meanwhile, donkeys sleep about three hours. Cats sleep
Speaker 3: twelve and a half hours a day, which seems like
Speaker 3: an underrested.
Speaker 6: Absolutely an addressment.
Speaker 3: Goats five point three on average, guinea pigs nine point four.
Speaker 3: I mean, just to show you, it's all over the map.
Speaker 3: And really many of these sleep duration estimates we do
Speaker 3: have to take with a grain of s because like
Speaker 3: we're measuring sleep in the lab, and so there tends
Speaker 3: to be a bias towards like longer sleep because they're like,
Speaker 3: I don't have to worry about predators. I've got food here,
Speaker 3: i've got water, I'm chillen. Might as well take a nap,
Speaker 3: might as well just nap all the time. But even still,
Speaker 3: we do have this huge variation in how much sleep
Speaker 3: different species need. But duration is just one component of sleep,
Speaker 3: as we talked about. There's also whether you sleep in
Speaker 3: one big chunk or multiple times throughout the day or
Speaker 3: throughout the night, like monophasic sleep is one big chunk,
Speaker 3: which is what humans usually do big asterisk on that,
Speaker 3: by phasic sleep, which is two chunks, which is what
Speaker 3: humans may be used to do, asterisk on that, or
Speaker 3: polyphasic sleep like multiple chunks, like a dog who sleeps constantly. Yeah.
Speaker 3: Whether you tend to sleep during the night time, during
Speaker 3: or during the day is another big component of this,
Speaker 3: like a red tailed hawk versus a barn owl for instance,
Speaker 3: talking birds and not all owls are nocturnal. A lot
Speaker 3: are crepuscular, So it took me a while to find
Speaker 3: one that I was like, it's a great word, crepuscular. Yeah,
Speaker 3: it's very good. There's also whether or not you have remsleep.
Speaker 3: So generally speaking, mammals and birds are the only animals
Speaker 3: with remsleep, except for maybe the cuttlefish. That's so weird,
Speaker 3: I know, I know, And not all mammals have sleep
Speaker 3: really yeah, okay, so side note, remsleep evolved after non
Speaker 3: remsleep as far as we can tell, and it's thought
Speaker 3: to have emerged in mammals and birds independently.
Speaker 6: Oh that's interesting.
Speaker 3: Yeah, so, which indicates that it might be really important
Speaker 3: for cognitive activities or warm bloodedness like aka and a thermy.
Speaker 3: Oh interesting, Okay, cuttlefish, I don't know.
Speaker 6: Cuttlefish are weird ones.
Speaker 3: They are so cute. But if you do have remsleep,
Speaker 3: you know how long are your sleep cycles between rem
Speaker 3: and non rem. So, for instance, you said human is
Speaker 3: ninety minutes, or so, the chinchilla is six minutes, six minutes.
Speaker 6: They go through a whole six minutes. Yes, Oh my gosh,
Speaker 6: you're like.
Speaker 3: Done and up. There's also whether you sleep with all
Speaker 3: of your brain or half of it.
Speaker 4: That's I think one of my favorite facts I learned
Speaker 4: in a children's book accidentally before we were It was
Speaker 4: called sleepy, and that is where I learned about uni
Speaker 4: hemispheric sleeping.
Speaker 3: Hemispheric sleep Yep, it's a real thing, sleeping with one
Speaker 3: eye open. It was a real thing. Aquatic mammals like whales, dolphins,
Speaker 3: and seals, as well as some bird species, especially those
Speaker 3: that are undergoing like long migrations, like.
Speaker 4: The what's someone that never touches the land for albatross.
Speaker 6: Yeah, is that it?
Speaker 3: Oh gosh, I don't know. Sorry, sorry ornithologists, But yeah,
Speaker 3: union hemispheric sleep. And we've got a little thing here
Speaker 3: that shows like the eeg of what it looks like
Speaker 3: when you have like once part of.
Speaker 6: The part of your brain is on and part of
Speaker 6: your brain is off. Yeah, Oh my gosh.
Speaker 3: That's so it's interesting, amazing in the right and the left. Yeah.
Speaker 3: And what's even weirder about this is that whales, dolphins,
Speaker 3: and porpoises who do this union hemispheric sleep, they don't
Speaker 3: seem to have rem sleep, or if they do, it's
Speaker 3: not in a form that we recognize.
Speaker 6: Oh that's so interesting.
Speaker 3: Yeah. So it's like, did they lose remsleep right when
Speaker 3: they went back to the oceans? Right, I don't know,
Speaker 3: I don't know. Okay, but why do aquatic mammals sleep
Speaker 3: with just one half of their brain? The mean a
Speaker 3: few different possible reasons, right, So one is because they
Speaker 3: need to breathe, right, and so they need to be
Speaker 3: able to come up and have that more active thing.
Speaker 3: Another is to reduce heat loss. Apparently it's supposed to
Speaker 3: help with like thermogeneration.
Speaker 6: Interesting, And a third is to be.
Speaker 3: On the lookout for predators, and a fourth is to
Speaker 3: stay close to one another because you can really drift
Speaker 3: apart because if you're just drifting. Yeah, like if you've
Speaker 3: seen those amazing videos of sperm whales all sleeping vertical
Speaker 3: and like a like a forest of sperm whales. Yeah,
Speaker 3: sea otters of course hold hands when they sleep, which
Speaker 3: is just it's so cute pain sleep cute yep. And
Speaker 3: unlike terrestrial mammals, newborn dolphins and orca whales are on
Speaker 3: the move from the first moment. And unlike human babies,
Speaker 3: which sleep, like you said so much, so randomly all
Speaker 3: over the place, these baby dolphins and orca whales are
Speaker 3: continuously active for like four weeks, like no sleep, you
Speaker 3: don't sleep at all, no sleep along with mom.
Speaker 6: Yeah, fascinating yep, yep.
Speaker 3: And it's only after those weeks that sleep gradually returns.
Speaker 3: And this might be because it's just a really vulnerable
Speaker 3: time for those babies, it. Yeah. And even when sleeping,
Speaker 3: these aquatic mammals are moving quite a bit. So dolphins
Speaker 3: make counterclockwise circles regardless of which half of the brain is.
Speaker 6: Sleeping counterclockwise circles.
Speaker 3: Why, great question. I do not know. I do not know.
Speaker 4: Counterclockwise circles regardless of which part of their brain is sleeping.
Speaker 4: That is so interesting. I do they sleep? Sorry, I'm
Speaker 4: gonna ask more details. Do they sleep?
Speaker 2: Like?
Speaker 4: Obviously it's one half at a time, but is it
Speaker 4: like consolidated like at night time they're gonna like, okay,
Speaker 4: forty minutes on this half and then forty minutes on
Speaker 4: this half or whatever.
Speaker 3: Question.
Speaker 6: I don't know.
Speaker 3: I don't know.
Speaker 6: Okay, I'm so I can said.
Speaker 3: There's a really great paper that I have I'll shout
Speaker 3: out at the end that has like a lot more
Speaker 3: information on this and even like pictures of dolphins sleeping
Speaker 3: at the bottom of like enclosures and whales and stuff
Speaker 3: like that. Yeah, yeah, okay. Fur seals listen to this description.
Speaker 6: It's very cute.
Speaker 3: When first seals sleep in water, they usually float on
Speaker 3: their sides, holding one front and two hind flippers in
Speaker 3: the air. The front flipper in the water constantly paddles
Speaker 3: something cute, and the rest are just like up in
Speaker 3: the air. One I always open and the other is closed. Wow.
Speaker 3: Fur Seals also are one of these creatures that spend
Speaker 3: some time on land and guess what their sleep is
Speaker 3: like on land like a dog, like any other terrestrial mammal.
Speaker 6: But when they're in the water they uni hemispheric.
Speaker 3: Uni hemispheric sleep. What And when they're on land, both
Speaker 3: eyes are closed and they cycle through REM and non rem.
Speaker 6: But when they're in the water they don't.
Speaker 3: Nope.
Speaker 6: Oh that is so interesting, I know, I know.
Speaker 3: Oh wow, it makes me like I never I mean,
Speaker 3: I have like thought about sleep mostly in like a
Speaker 3: very selfish like am I sleeping enough? Oh my gosh,
Speaker 3: my sleep kind of away? But this is maybe more
Speaker 3: interested in rem sleep than like ever.
Speaker 6: Yeah yeah, same, Yeah, I did not know any of that.
Speaker 3: Yep either. How interesting it's amazing. Yeah, okay, So, but
Speaker 3: the fact that sleep comes in all shapes and sizes
Speaker 3: across the animal kingdom and is even variable, like you said,
Speaker 3: within an individual's life, it shows us that sleep is
Speaker 3: not random, right, how species sleeps is the outcome of
Speaker 3: millennia of adaptations. Nor is sleep rigid? Right? There may
Speaker 3: be times when when we need to go with less sleep,
Speaker 3: then we you know, ideally like to have migration, mid terms,
Speaker 3: having a newborn, I love it, socializing stress. You know,
Speaker 3: there's a lot of different reasons that might affect our
Speaker 3: sleep duration, and we can do that, we can sleep
Speaker 3: with we can have less sleep than we'd like for
Speaker 3: a limited like a certain amount of time, and then
Speaker 3: our bodies know to recover from.
Speaker 6: That sleep debt.
Speaker 3: So if the way that we sleep is not random,
Speaker 3: what determines how species sleep? Why does a chinchilla have
Speaker 3: a six minute that? I can't answer that. I don't
Speaker 3: know about that, but it is. It is a great
Speaker 3: question overall, and we don't exactly know. And so there
Speaker 3: are some general patterns that I'll take you through. But
Speaker 3: to every pattern there's an exceptions. So if we take
Speaker 3: all that we know about sleep in animals and we
Speaker 3: look for similarities after controlling for how related, they are
Speaker 3: a few strong drivers emerge predation, metabolism, immune function, gestation, length,
Speaker 3: brain mass, and neuroanatomical regions like the amygdala.
Speaker 4: So these are all the parts of things that are
Speaker 4: contributing to how long and how an animal is sleeping.
Speaker 3: Mostly I would say, like how long and the polyphasic
Speaker 3: versus got it? Yeah, yeah, monophasic, et cetera. Okay, And
Speaker 3: I don't like there are some aspects of REM and
Speaker 3: non REM, but like that, I mean, it's just like
Speaker 3: it's really difficult to draw any sort of yeah, like parallels.
Speaker 4: Well, and I feel like it's so interesting because one
Speaker 4: of the books that I read it was like how
Speaker 4: you define sleep in animals, Like with this behavioral thing
Speaker 4: then also affects how we think about and look at.
Speaker 6: The why of sleep.
Speaker 4: Right, if you define it in slightly different ways, then
Speaker 4: you might come to a different conclusion as to the
Speaker 4: function of sleep.
Speaker 3: It's a little bit of a guiding hypothesis, that's kind
Speaker 3: of a thing. Yeah, and you're like, well, if if
Speaker 3: REM is really the questions that you're asking are driving
Speaker 3: that how you're looking.
Speaker 4: For data, if you're only counting REM sleep as sleep,
Speaker 4: then your conclusions are going to be totally different.
Speaker 3: Or is more REM sleep better?
Speaker 4: Right?
Speaker 6: Yeah, it's so interesting.
Speaker 3: It's really interesting. Okay, so let's talk about some of
Speaker 3: these some of these different factors. When you're sleeping, you
Speaker 3: are in a vulnerable state. Your senses are dulled, so
Speaker 3: you can't hear that twig snap, and you're laying there motionless,
Speaker 3: looking like a nice tasty snack for that tiger that's
Speaker 3: you know, just caught your scent and creeping away from there,
Speaker 3: creeping towards you. Actually creeping away would be great. So
Speaker 3: you might be a little better off if you had
Speaker 3: like a burrow or a tree hole to nestle into.
Speaker 3: But if you just PLoP down in an exposed area,
Speaker 3: you're you're playing a very risky, very risky game. Yeah,
Speaker 3: and so to lower that risk, you might sleep less.
Speaker 3: And that is what we tend to see. Prey species
Speaker 3: or species that sleep in more vulnerable locations, like on
Speaker 3: the ground, as opposed to like in the tree, they
Speaker 3: tend to have shorter sleep durations. Interesting and in one experiment,
Speaker 3: rats that encountered a predator got less sleep afterwards both
Speaker 3: and they were like edge, you're just on edge. You
Speaker 3: got to be like you're in lighter sleep. I guess
Speaker 3: some research actually, some researchers actually suggest that light sleepers
Speaker 3: and people with insomnia might have those predator or biting
Speaker 3: insect vigilance mechanisms on overdrive. So if you're like someone
Speaker 3: who is really hard time getting into like your wake
Speaker 3: at the drop of it, like just a little rustle, yeah,
Speaker 3: you might be. It's just it's adaptive, not anymore of
Speaker 3: those you won't get eaten. It once was adaptive. Yeah,
Speaker 3: and so sleeping in larger groups, like larger social groups,
Speaker 3: that might help counteract them the vulnerability to predators while
Speaker 3: you're sleeping. But then there's also the trade off of
Speaker 3: social disturbances and parasite transmission.
Speaker 6: Because you're just like alltogether.
Speaker 3: Yeah, but so it's like sleep alone and be easier prey,
Speaker 3: or sleep in a group and get less sleep, not
Speaker 3: necessarily worse, but like, and maybe it's more efficient sleep,
Speaker 3: but it does seem like sometimes it's shorter sleep okay. Interesting,
Speaker 3: or you could sleep while your predators also sleep okay,
Speaker 3: and predators tend to get more sleep just on average.
Speaker 3: You're like, it's fine, bro right, Like I'm chilling. And
Speaker 3: metabolism might also play a role in that when it
Speaker 3: comes to predators versus prey because herbivores, which are more
Speaker 3: generally more often prey, they need to eat more frequently
Speaker 3: because they have faster metabolisms or like their food is
Speaker 3: less calorically dense, and so they have to spend a
Speaker 3: good chunk of their time foraging, especially if their food
Speaker 3: is their preferred food is dispersed across the landscape, like, oh,
Speaker 3: I have to get fruit trees, and I have to
Speaker 3: go far to find them, and so you're like you're commute,
Speaker 3: its long.
Speaker 6: Got it?
Speaker 3: And you're like, I got to get back to my
Speaker 3: little burrow.
Speaker 6: Yes.
Speaker 3: Yeah. Animals with faster metabolisms relative to body size also
Speaker 3: sleep less and smaller animals tend to sleep throughout the day.
Speaker 3: They're polyphasic sleepers immune function, so we all know that
Speaker 3: not getting enough sleep leaves us more vulnerable to infections,
Speaker 3: and some studies us that species with longer sleep durations
Speaker 3: have higher white blood cell counts and are less likely
Speaker 3: to be parasitized.
Speaker 6: Interesting.
Speaker 3: I think this is a very big generality exactly.
Speaker 6: Yeah.
Speaker 3: And finally, oh, there's also gestation length. So longer gestations
Speaker 3: are associated with shorter sleep.
Speaker 4: So that's why, like elephants you said get only four hours. Yeah,
Speaker 4: that's really weird though, why maybe it's just a correlation.
Speaker 3: Yeah, it could be they're all metablet I don't. I mean,
Speaker 3: that's like a lot, and this is like a very
Speaker 3: much and I don't know episode how interesting though. And
Speaker 3: then finally, bigger brains like body size. Yeah, and proportion
Speaker 3: of body size equals a bigger chunk of time spent
Speaker 3: in REM.
Speaker 6: Sleep in REM sleep specifically.
Speaker 3: Okay, but again this is all messy. So there was
Speaker 3: a cool paper though I read that showed how vastly
Speaker 3: different sleep could be for two closely related species and
Speaker 3: how similar it could be for distantly related species. So,
Speaker 3: for since the domestic cat and its relative the genet,
Speaker 3: a cat gets around twelve and a half.
Speaker 6: Hours of sleep, like I said a day with.
Speaker 3: Three point two hours REM, and a genet gets about
Speaker 3: half that six point three hours with one point three
Speaker 3: hours RIM. And those are like closely related species.
Speaker 4: Yeah yeah, and I is that just like because domestic
Speaker 4: cats are just chillen.
Speaker 3: They might be just domestic cats. Yeah. But then there's
Speaker 3: also a golden mantled ground squirrel and a daegu, again
Speaker 3: closely related. The squirrels fifteen point nine hours of sleep
Speaker 3: with three in REM and seven point seven for the
Speaker 3: daegu with point nine in REM.
Speaker 6: How interesting.
Speaker 3: So it's not just about like domestication, although I'm assuming
Speaker 3: that is a decent part of it for the cat.
Speaker 6: Yeah.
Speaker 3: Then take a guinea pig in a baboon, not closely related,
Speaker 3: but their sleep architecture is or they're not architecture, their
Speaker 3: sleep like duration and REM proportion is very similar. They
Speaker 3: each get about nine point four hours of sleep and
Speaker 3: one of REM.
Speaker 6: That's so interesting.
Speaker 3: And in case you were wondering for humans humans, we
Speaker 3: humans get the same amount of sleep as an Eastern
Speaker 3: American mole. We get seven to eight hours and we
Speaker 3: both have about two hours sleep REM. Oh, my gosh. Interesting,
Speaker 3: that's funny. Yeah, it's really funny. But among primates though
Speaker 3: humans are the exception, we are at the very extreme
Speaker 3: end of sleep duration, with some of the shortest sleeps
Speaker 3: of all primate species. The shortest sleeps.
Speaker 4: Yeah, the shortest sleep of all primates.
Speaker 6: Yep, huh yeah.
Speaker 3: On the other end of the spectrum are owl or
Speaker 3: night monkeys owl monkeys or night monkeys, which sleep about
Speaker 3: seventeen hours, but they get the same amount of REM
Speaker 3: sleep as humans.
Speaker 6: That is so interesting. Yeah, oh, I do want to
Speaker 6: look so much more into REM now. I know, right,
Speaker 6: what is up with that?
Speaker 3: I know what is up with that sleep?
Speaker 6: What is up with that?
Speaker 3: Based on our human body size, body or brain size,
Speaker 3: body mass, predation, risks, foraging needs, sexual selection, dynamics, diet,
Speaker 3: and what we know about other primates like researchers have
Speaker 3: kind of compiled this model to be like, how should
Speaker 3: we how should we expect humans to sleep based on
Speaker 3: what we know about all other primates? And that comes
Speaker 3: out to nine and a half hours a night.
Speaker 4: That's how much we should be getting housted.
Speaker 3: Based on these that is not and but we on
Speaker 3: average it's six to seven hours for humans. And this
Speaker 3: does not mean that we should all be sleeping nine.
Speaker 6: And a half hours.
Speaker 3: It's just what the model predicts based on other primates.
Speaker 4: So it shows that we are weirdos.
Speaker 3: Yes, because evidence, I mean, evidence points to six to
Speaker 3: seven is normal sleep or six to eight is normal
Speaker 3: sleep in humans. And it might just be that we
Speaker 3: somehow squeezed our sleep into a shorter duration, like we're
Speaker 3: more efficient or intense sleepers. Other grade apes sleep a
Speaker 3: bit more than humans, but less than like night out
Speaker 3: or night monkeys and like chimpanzees get about ten hours
Speaker 3: with similar rem as humans, and gorilla sleep about twelve,
Speaker 3: orangutangs sleep about nine, slightly rest less than humans. But
Speaker 3: when it comes to humans and other great apes, we
Speaker 3: do share other characteristics. So we have this high proportion
Speaker 3: of rem sleep and we have nesting behavior, which I
Speaker 3: just think is adorable. Many of the over four hundred
Speaker 3: primate species that exist sleep in trees, whether that's in
Speaker 3: tree holes or on bear branches, just like balancing up there.
Speaker 3: Even if they spend like much of their waking time
Speaker 3: on the ground, they will sleep in the trees. And
Speaker 3: this might help with like predator avoidance. Probably other species
Speaker 3: might sleep individually, or they might sleep in groups, or
Speaker 3: they might sleep on bare ground or on cliffs, like
Speaker 3: baboons sleep on cliffs and on bare grounds. And some
Speaker 3: build nests mostly in trees. In fact, all great apes
Speaker 3: build nests, all of them.
Speaker 6: I did not know that.
Speaker 3: Yeah, me either. Yeah, And so this suggests that the
Speaker 3: behavior emerged about fourteen to eighteen million years ago. Interesting,
Speaker 3: they are built individually, they take between one to seven
Speaker 3: minutes to construct, and they're usually built every night with
Speaker 3: occasional reuse.
Speaker 6: So they just make their own new nests.
Speaker 3: To make their own new nest, yeah, with a bunch
Speaker 3: of different materials. It's there is so much more about
Speaker 3: nest building. And I have a paper too, and so
Speaker 3: why did we start to build nests. It's thought that
Speaker 3: as body size got bigger in these great ape species,
Speaker 3: they probably helped to make sleeping more comfortable overall and
Speaker 3: to protect against damage. If you like fell out of
Speaker 3: a tree, then like your body.
Speaker 6: Was just like a little cushion.
Speaker 3: You've got some cushions, so like you're yeah, it makes
Speaker 3: it more comfortable. And so this also helped to avoid predation.
Speaker 3: So research suggests that chimpanzees build nests higher and in
Speaker 3: closer proximity to each other in places when there are
Speaker 3: where there are more predators. Ah, and also thermal regulation,
Speaker 3: so you can decide, Okay, is your nest placement going
Speaker 3: to be higher up or lower down? Do I need
Speaker 3: more insulation? Do I need to pack in some more leaves,
Speaker 3: keep chilli night? Is it nice and warm? You know,
Speaker 3: like I want to get a breeze up in there.
Speaker 3: And finally, nests may also help to deter biting insects.
Speaker 3: So researchers found that some orangutanks built their nests near
Speaker 3: naturally mosquito repellent tree species when mosquitoes were abundant.
Speaker 6: I love this so much, I know.
Speaker 3: I mean, if you think about nest building is an
Speaker 3: incredible behavior and there are some researchers that categorize it
Speaker 3: under tool use, which would make it the most pervasive
Speaker 3: among great apes. Wow, yeah, it's environmental problem solving when
Speaker 3: it comes down to it. Did great apes build nests
Speaker 3: because they were smart? Or did building nests help make
Speaker 3: evolve smartness evolve enhanced cognition in Elisha, yeah, chicken or egg?
Speaker 3: I don't know.
Speaker 6: Yeah, I don't know.
Speaker 3: But so, like I mentioned, most of these nests are
Speaker 3: in trees. But humans have long slept on the ground,
Speaker 3: despite the ground making us more vulnerable to predators, and
Speaker 3: some researchers have suggested that this ground sleeping, with its
Speaker 3: more stable surface, would have enabled even deeper sleep, which
Speaker 3: then allowed us to sleep more intensely fall right, we
Speaker 3: don't have to have that increased vigilance as much, and
Speaker 3: so that's what maybe allowed us to shorten our sleep duration.
Speaker 3: And then once humans developed the ability to control fire,
Speaker 3: that would have cut down on the risk of predators
Speaker 3: and biting insects, and it would have increased our thermoregulation
Speaker 3: capacities while allowing us longer hours to socialize into the night,
Speaker 3: exchanging ideas and storytelling, maybe even promoting the evolution of language.
Speaker 3: And so in short, sleeping on the ground helped to
Speaker 3: make us become human. Oh right, once we made it
Speaker 3: there on the ground. What happened then? Did we just
Speaker 3: stick to our six to eight hours a night with
Speaker 3: no breaks? Or is the story slightly more complicated than that.
Speaker 3: I'm leaving you on a cliffhanger, so you'll have to
Speaker 3: tune in next week to find out. But I hope
Speaker 3: you liked this little hodgepodge of a tour through animal
Speaker 3: kingdom sleep.
Speaker 6: I loved it.
Speaker 3: It's not a mistake. No, sleep is not a.
Speaker 6: Mistake, not an evolutionary mistake.
Speaker 3: I think that was mostly said tongue and totally sounded
Speaker 3: like it.
Speaker 2: Yeah.
Speaker 4: Oh that was really fun and it made me really
Speaker 4: excited to find out what humans did with our sleep.
Speaker 3: I can't wait to tellt you.
Speaker 6: I mean, I don't sleep on the floor.
Speaker 3: I don't sleep on the floor. I have slept on
Speaker 3: floors many times, or on preferred benches. It's horrible.
Speaker 4: So I can't wait to hear what we did when sleep.
Speaker 6: Well.
Speaker 3: In the meantime, there's a lot more reading. You shall
Speaker 3: we tell the people where to read?
Speaker 6: Let us okay, I tell them.
Speaker 3: I have many sources, many sources for this one, because
Speaker 3: I just kept going down rabbit holes.
Speaker 6: I loved them all. We didn't even talk about rabbitsleep, didn't.
Speaker 3: I actually did have a section where I was I
Speaker 3: went through each of the animals on my jas to
Speaker 3: be like, raccoon sleep, this amount, possum sleep, this amount,
Speaker 3: my favorite animal besides the Tasmanian douvile.
Speaker 6: Squirrels, et cetera.
Speaker 3: And I cut it because I was like much, it's
Speaker 3: way too many animals. Okay, you can find more information.
Speaker 3: There's a book about a lot of animal sleep called
Speaker 3: Evolution of Sleep, Phylogenetic and Functional Perspectives by McNamara at
Speaker 3: all from twenty ten. Then there's a great paper I
Speaker 3: loved from two thousand and eight called Unearthing the Phylogenetic
Speaker 3: Roots of Sleep by Aladda and Seagull from two thousand
Speaker 3: and eight. I think I already said two thousand and
Speaker 3: eight multiple times by liaman at All from two thousand
Speaker 3: and eight as well Cetacean Sleep, An Unusual Form of
Speaker 3: Mammalian Sleep, and finally by Fruth and Stewart, Sleep and
Speaker 3: Nesting Behavior in Primates a review.
Speaker 6: Love it, great stuff. I had.
Speaker 4: Most of this information that I shared came from a
Speaker 4: book from twenty twelve that was called sleep a very
Speaker 4: short introduction from Oxford University Press. It covers all the
Speaker 4: But I also enjoyed a paper from Physiological Reviews from
Speaker 4: also twenty twelve that's weird, that was called control of
Speaker 4: Sleep and Wakefulness by Brown at All. And then the
Speaker 4: paper that was not funded by industry about the wearable
Speaker 4: finger tracker ring sleep measures was from Scientific Reports published
Speaker 4: this year twenty twenty five.
Speaker 3: Trying so hard not to say any brand name.
Speaker 6: I know you know the ones.
Speaker 4: I guess twenty twenty five is last year by the
Speaker 4: time this comes out, doesn't matter anyways. It was by
Speaker 4: Herberger at all and it was titled performance of Wearable
Speaker 4: finger ring Trackers for diagnostic sleep measurement in the clinical context.
Speaker 4: But I have other ones as well to you, and
Speaker 4: so many more papers, so you can read them all
Speaker 4: and find them all on our website.
Speaker 6: This podcast will kill you dot com.
Speaker 3: We will post them all there. Stephen Ray Morris, thank
Speaker 3: you again, what an absolute delight. It was, really, Thank
Speaker 3: you so much for sharing your story. Also, sorry that
Speaker 3: you've had sleep proless. No we're not saying your sleep press.
Speaker 6: This was a delight.
Speaker 3: No hearing your voice. Hearing your sharing your story, it
Speaker 3: was wonderful. Thank you and thank you also to Bloodmobile
Speaker 3: for preventing the music for this episode, in all of
Speaker 3: our episodes, thank.
Speaker 6: You, thank you.
Speaker 4: Thank you to everyone here and Exactly Right Studios, as
Speaker 4: well as everyone who helps make this podcast possible.
Speaker 3: Yes, including you listeners. Thank you for listening, patrons. Thank
Speaker 3: you for patroning your patrons.
Speaker 6: Patrons.
Speaker 3: Yeah, thank you for everythank you.
Speaker 6: Wow.
Speaker 3: Until next time, wash your hands animals
Speaker 2: A